Copy multiple structs into a buffer using memcpy in c -


  1. i have several structs (of u8 fields) want convert buffer, best way?

    struct struct_a a; struct struct_b b; u8 buffer[64]; u8 *next_pos;  os_memcpy(buffer, &a, sizeof(struct_a));  next_pos = buffer + sizeof(struct_a)/sizeof(u8);  os_memcpy(next_pos, &b, sizeof(struct_b));

  2. is best way calculate overall length of buffer?

    buffer_len = (sizeof(struct_a) + sizeof(struct_b) + ... )/sizeof(u8);

thanks

i assume u8 means unsigned 8 bits. hence, sizeof(u8) equals 1. can write:

os_memcpy(&buffer[sizeof(struct_a)], &b, sizeof(struct_b));

for second question, except dividing 1 useless, it's fine way compute len of buffer.

i'm not big fan of buffer + sizeof(struct_a) it's good.

edit: also, when doing kind of stuff, if size of elements of buffer not 1, cast buffer equivalent of u8. way, don't have divide size of elements of buffer.


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